In the prior art, damping is used to reduce the amplitude of resonant vibration in mechanical assemblies by converting a portion of the energy into low-grade heat, often with the use of elastomeric materials. Typically, such vibration damping materials use a mechanism known as hysteretic damping to dissipate energy. When these materials are deformed, internal friction causes high energy losses to occur.
FIG. 1 shows a prior art vibration damping assembly as applied to two rigid plates 24 and 26. As shown in FIG. 1, an elastomeric isolation mount as denoted by number 29, is placed between the rigid plate members 24 and 26 to absorb vibratory energy in the plates. A bolt 29A and nut 29B couple the plates 24 and 26 together while maintaining the isolation mount 29 under compression. The isolation mount is made of a material with high loss factor, for example, materials manufactured by E-A-R Specialty Composites, carrying the trademark ISODAMP®.
One disadvantage of the prior art assembly shown in FIG. 1 is that the bolt 29A used for coupling plates 24 and 26 together is made of a rigid material with low loss factor, for example, steel, for effecting a secure connection. The bolt 29A, although isolated by an isolation material 28, as shown in FIG. 1, downgrades the damping effect of the damping assembly.